This, and the following paper, were first presented during the European GNSS98 Symposium held at the Centre de Congrès Pierre Baudis, Toulouse, France, from 20 to 23 October 1998; however, both authors have provided updated scripts for use in this Volume of the Journal.

This paper provides an update of the development and implementation of the United States of America Federal Aviation Administration (FAA) Wide Area Augmentation System (WAAS) and Local Area Augmentation Systems (LAAS). It also addresses FAA efforts to implement these satellite navigation technologies into the US National Airspace System (NAS), as well as interoperability efforts concerning Satellite Based Augmentation Systems (SBAS) between the FAA and other worldwide Civil Aviation Authorities.

This paper presents the application of GNSS1, or more precisely of Satellite Based Augmentation Systems (SBAS), to vertical separation for en-route, approach and landing operations. Potential improvements in terms of operational benefit and of safety are described for two main applications. First, vertical separation between en-route aircraft, which requires a system available across wide areas. SBAS (EGNOS, WAAS, and MSAS) are very well suited for this purpose before GNSS2 becomes available. And secondly, vertical separation from the ground during approach and landing, for which preliminary design principles of instrument approach procedures and safety issues are presented. Approach and landing phases are the subject of discussions within ICAO GNSS-P. En-route phases have been listed as GNSS-P future work and by RTCA for development of new equipments.

Operating a fleet of ships in all weathers and environments poses certain risks, and navigational incidents such as collisions, groundings and vessel strikings are bound to occur. The Royal Navy has always conducted extensive inquiries into the serious navigational incidents in order to establish the cause and so prevent reoccurrence. However, many less serious navigational incidents occur which, if collated and analysed on a database, could help better understanding of the nature of such incidents. This paper describes how a database that met these needs was designed and developed. Once completed, the database was analysed to compare trends between different vessel types and incident categories.

With the assistance provided by the white cane or guide dog, most blind pedestrians can find their way to known destinations along familiar routes. Finding new or known destinations along unfamiliar routes is more challenging. Before such a journey is attempted, detailed instructions must be acquired. The difficulty of obtaining and then reliably following such instructions deters many blind pedestrians from travelling alone in unknown areas. This paper demonstrates a technological approach, by way of field trials, that supplements the existing aids and eliminates the need for sighted guides. The approach has the potential to offer greater independence to the blind person. The investigation suggests that the methodology used in personal navigation systems for the sighted is sub-optimal for guiding the blind pedestrian. Suitable extensions are introduced, and the results show the proposed methodology is efficient for guiding the blind individual to unknown destinations in the chosen field trial environment.

This paper presents the results of a study carried out in the Greater London area to assess and characterise the performance of the Global Positioning System (GPS) for vehicle positioning in urban areas. The performance assessment addresses, in varying levels of detail, the issues of service coverage, positioning accuracy, integrity and availability of service. The project was supported by Racal Survey Limited and is part of the wider research at Imperial College in the area of architectural design and testing of Advanced Transport Telematics (ATT) systems. The results highlight the shortcomings of GPS as the sole means for in-car navigation in urban areas and details the temporal and spatial considerations to be taken into account in the process of designing an integrated positioning system capable of meeting navigation requirements placed on ATT systems.

The Instrument Landing System (ILS), in its present 90/150 Hz format, had its beginnings in the United States and England during the years 1939 to 1945. Since then, it has served the aviation community worldwide. There have been many improvements to cope with ever increasing traffic, crowded airports, and difficult siting problems. There are those who say that it's time to replace the system with newer technology; are they right?

Digital electronics have caused massive changes to navigation technology in the latter half of the twentieth century. This paper presents an alternative view to much of the commentary on the future of electronic navigation. It is written from a small craft perspective, although the principles are of value to commercial and naval shipping. Essentially, it proposes the development of environmental simulation as the basis for computer-hosted charting systems on vessels. This is drawn from the author's experience of developing the DyGeo system for environmental simulation, of which the navigation version forms a part. It stresses that much of the additional data we have placed on charts this century has been cultural in content, and necessitates a large bureaucratic system for its maintenance. An environmental system requires different types of inputs, but can be largely self-maintaining. The advent of the inexpensive, portable, personal computer has put this sort of facility in the hands of the leisure mariner as well as professional navigators.

In this paper, the ship manoeuvring problems particular to maritime search and rescue are investigated. A solution to such problems is necessary for successful ship handling to save human life. A fuzzy gain scheduling Proportional Derivative (PD) controller, using a back-propagation algorithm, is developed to solve these maritime search and rescue problems. The parameters of the proposed PD controller are determined on-line by fuzzy rules and adjustable fuzzy reasons. The proposed controller is self-adaptive and can accommodate the effects caused by wave or wind disturbance. Some computer simulations are provided to illustrate the use of the main ideas.

This paper describes an algorithm for evaluation of magnetic compass deviation based on the least squares method. An automatic system was built, coupled with a magnetic compass recording device, for fine estimation of the deviation curve on the basis of an incomplete compass swing circulation.

During the past thirty years, there has been a steady growth in the size and number of ships that use the Strait of Istanbul (Bosporus), which is one of the most difficult, crowded, and potentially dangerous waterways in the world. There have been over two hundred accidents over the past decade resulting in loss of life and serious damage to the environment. Many of the proposed export routes for forthcoming production from the Caspian sea region pass westwards through the Black Sea and the Bosporus en-route to the Mediterranean Sea and world markets. The risks and dangers associated with tanker navigation, maritime accidents and environmental catastrophe are aggravated with the increase in the density of traffic, tanker size and cargo capacity, as well as the nature of the cargo. In order to ease the problem, a Traffic Separation Scheme (TSS) was established and approved by IMO in 1994. This scheme has drastically reduced the number of collisions. However, one-way or two-way suspension of traffic in the Bosporus is inevitable for ships that cannot comply with the TSS because of their type, size or poor manoeuvring characteristics. The selection of size criteria to comply with the TSS has been a matter of discussion. This paper presents the results of a real-time simulation study investigating the manoeuvring performance of large tankers in the Bosporus. The study was conducted with a simulator capable of subjecting a given hull form to any combination of environmental conditions, i.e. wind, current and wave drift forces. The results indicate that, when realistic environmental conditions are taken into account, the size of ships that can navigate safely in compliance with the traffic separation lanes is limited.

Low frequency radio navigation systems continue to play an important role in the provision of precise navigation for vessels sailing in coastal waters, and in other zones requiring high accuracy. Modernization of the existing Loran C chains, and deployment of new ones, shows there is strong interest in these systems despite the appearance of global navigation satellite systems (GNSS) such as ‘Navstar’ and ‘Glonass’. This continuation of interest is connected to the relatively low cost of operation of the systems, the low cost of receiver-indicators and the need to provide users with very precise but reliable positioning information, which at present can only be obtained by joint use of GNSS and Loran C. To make the most of such an approach, Loran C should provide accuracy and reliability similar to GNSS.

A curve that cuts all meridians of a rotating surface at the same angle is called a loxodrome. If the shape of the Earth is approximated by a sphere, then the loxodrome is a logarithmic spiral that cuts all meridians at the same angle and asymptotically approaches the Earth's poles but never meets them. Since maritime surface navigation defines the course as the angle between the current meridian and the longitudinal direction of the ship, it may be concluded that the loxodrome is the curve of the constant course, which means that whenever navigating on an unchanging course we are navigating according to a loxodrome.

The normal Great Circle method of computing the shortest distance between two positions on the Earth – e.g. from an aircraft's present position (PP) to a waypoint (WP) – is not accurate enough to meet present-day requirements for aircraft Nav–Attack systems.

On the surface of an Ellipsoid (or Spheroid), the true ‘shortest distance’ is along a geodesic curve between the two points, but the computation of this curve is complex, and as shown by R. Williams at Reference, the difference between the geodesic and Great Ellipse distances between two points is negligible (<0·01 nm).

The Great Ellipse through two points on a spheroid is defined as the ellipse that passes through the two points and the centre of the spheroid; it therefore has a major axis equal to the Earth's, and a minor axis that is between the Earth's major axis (for two points on the Equator) and minor axis (for two points on the same, or diametrically opposite, longitudes). Thus the problem of deciding on which Great Ellipse the two points lie is equivalent to determining the magnitude of the minor axis β of the ellipse on which they both lie.

Sir Laurence Kirwan, Director and Secretary of the Royal Geographical Society from 1945 to 1975, and one of the founders of the Institute, of which he was an Honorary Member, died in London on 16 April 1999 aged 91. The events that took place early in 1946, and led to the foundation of the Institute of Navigation the following year, have been well documented by Pat Hansford in his article in the special issue of the Journal (September 1997) published to commemorate the Institute's fiftieth anniversary. Kirwan was a member of the original Steering Committee and then of the Provisional Council which undertook the preliminary work that culminated in the inaugural meeting in March 1947. He served on the first elected Council as Chairman of the Executive Committee, which in those days assumed responsibility for administering the Institute between meetings of the Council.

In his article, Hansford recalls how the Royal Society, when approached about the formation of the Institute, had suggested that (in the somewhat uncertain situation immediately after the war) the new body might thrive best, at any rate to start with, under the aegis of an existing scientific society with similar objectives. Kirwan, then the recently appointed Director of the Royal Geographical Society, took the suggestion up by proposing various ways in which the RGS might assist the new body, and notably by offering it accommodation; and the Institute has, of course, been at the Society's house ever since. The original accommodation was not lavish but, quite apart from the prestigious address and pleasant and appropriate surroundings, the facilities available included the use of the Society's lecture theatre and the Council and committee rooms. It is difficult to see how the new body, with a handful of members and no money, could have survived without some such assistance. But it was perhaps at a deeper level that the arrangement was to prove so influential, for it brought the young Institute into immediate contact with the liberal traditions of the learned societies in this country, concerned essentially with the subject rather than the benefit of its members, no doubt very much as the Royal Society would have wished.